Portable dock scaffold



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PORTABLE DOCK SCAF'FOLD J. L. THOMPSON EIAL June 3, 1952 Filed March 5,1948 June 1952 J. L. THOMPSON ETAL 2,598,730

PORTABLE DOCK SCAFFOLD Filed March 3. 1948 2 SHEETSSHEET 2 INVENTORSJOHN L. THOMPSON JOHN BIBB i W BY T? W ATTORNEY Patented June 3, 1952PORTABLE DOCK SCAFFOLD John L. Thompson, Dial, and John Bibb,

Port Hueneme, Calif.

Application March 3, 1948, Serial No. 12,844

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3700. G. 757) 4 Claims.

'IShis invention relates to portable scaffolds, and more particularly toa portable scaffold capable of being positioned to give access to theunderside of piers and docks.

Underneath a typical waterfront dock there are numerous operations whichmustbeperiodically performed. Oil lines and other plumbing must :berepaired and inspected. Telephone wires and electric wiring oftenrequire servicing. Tension members holding posts and bollards often needtightening. Braces must often be shimmed as they shrink with the passageof time. The bolts and nuts which hold the timbers together often mustbe cleaned-and'painted. In addition, it is necessary to inspect theunderside of docks as a matter of general preventive maintenance.

It is an object of this invention to provide a portable scaffold whichmay be readily moved into place beneath a .dock,whereby necessaryoperations under the dock may be performed.

It is another object of this invention to provide a'portable scaffoldwhich may be simply and detachably mounted to the lift fork of a truck,which truck may'then be used to transport the scaffold to variouslocations and lower it into place underneath the dock.

It is another object of this invention to obviate the cost and timeinvolved in constructing temporary-scaffolding under a dock, by using acompletely portable scaffold which has no attachment whatever to thedock, being positioned in place solely by the proper disposition of thelift "truck which carries it about.

'It is a further object of this inventionflto provide a portablescaffold for use under docks whereby the safety, health, and convenienceof maintenance and service personnel maybe enhanced.

In accordance with this invention, .the scaffold comprises a horizontal,generally elongate frame, from one end .of which depends :a pair ofvertical frames. To the bottom edges of the frames is secured ahorizontal platform extending beneath the horizontal frame. Thehorizontal frame includes .a pair of transverse girders, one of thembeing disposed at the end of the frame, the other -being spaced inwardlyof the frame. The inward girder is secured to the frame in a planeslightly above that of the outward girder, so that the frame may beheldto the horizontal extending fork of a lift truck, with the outer girderdisposed immediately under the fork, and theinward girder disposed,above 2 supported in cantilever fashion, With the platform dependingbelow the fork of the truck.

In use, the truck is driven to the edge of the dock, and stopped withthe front wheels abutting the barricade timber. The fork is thenlowcred, thereby lowering the entire scaffold over the edge of the dock.When the horizontal, upper frame is almost touching the timber, thetruck is backed away until the vertical frame almost touches the edge ofthe dock, thus positioning the platform in under the dock.

A gangplank is telescopically mounted beneath the platform, so that itmay be extended for added length, to enable the workmen to get infarther under the dock. A ladder is vertically secured between thehorizontal frame and the platform to provide access to and fromtheplatform when it is in position under the dock.

The horizontal frame is strengthened against bending by the provision ofa vertical bridge frame secured transversely to and above the horizontalframe, which serves to mount an elongate member in the form ,of a Tsectioned beam anchored at its respective ends to the ends of thehorizontal frame, and extending up and over the edge of the bridgeframe, to which it'is secured. In this way the effective section modulusof the horizontal frame is made great enough to accept the weight of theplatform and th workmen thereon.

A preferred embodiment of the instant invention is'shown in the drawing,wherein:

Fig. 1 is a side View of the scaffold;

Fig. 2 is an end view thereof;

Fig. '3 is a detailed view showing the manner in which the telescopinggangplank is mounted beneath the platform;

Fig. 4 is a fragmentary enlarged view showing the mounting of atelescoped hand rail for the g-angplank;

Fig. 5 is a View showing the scaffold secured to its fork lift truck, inposition to be lowered over the edge of the dock; ,and

Fig.6 is a view v,sllowing'thescaffold in use with the .gangplankextended to give maximum access to the underside of the dock.

Referring to Fig. 1, there is shown a horizontal frame H, comprised of.a pair of longitudinal channel beams i 2 secured together by transversegirders .I3 .M, .and 15. The girder L5 is disposed at one end of theframe 1 I and is attached to the bottom ,edge of the beams l2. Thegirder i4 is secured transversely of the frame H,:-inwardly of thegg-irder I15. is attached at the top'edge the 9f the fork. in this waythe frame is cf themember l2- fIhe-two gi de s-J nd 1-5 to the loweredges of which is secured a horizontal platform I8 extending inwardlyunderneath the frame II, the general effect of the scaffold being thatof a U tipped on its side. i The section modulus of the frame [I alone inot enough to support the overhanging weight of the structure dependingtherefrom. It is therefore necessary to strengthen the frame II by 1securing thereabove' a vertical bridge frame 2|, 1 consisting of a pairof upright members 22 anchored to the respective beams I2 and bridged bya horizontal member 23. The frame 2| is strengthened by diagonals 24.Elongate tension members in the form of T sectioned beams 25 are securedat their respective ends to the ends of the frame I I, and extend up andover the edge of the vertical bridge 2|, to which they are secured as bywelding at 25. The bridge member 2| is preferably disposed in the samevertical plane as that occupied by the transverse girder 4, therebyproviding maximum section modulus for the given type of construction.

Tension members 3| are diagonally mounted within the vertical frame I!to lend added strength thereto. Similarly, diagonal members 32 aremounted between the two frames transversely of the scaffold at the endof the frame I 2,

to give strength to the assembly.

Beneath the platform [8, the two edges of which are formed of channelmembers 33 (Fi 3). is telescopically mounted a gangplank 34, which maybe extended from the platform I8 as shown 3 inFig. 1 to give accessfarther in under the dock.

Balustrades 35 at the end of the platform provide for mounting handrails 36, formed of angle iron,

in which are secured, as by welding, pipes 31 (Fig. 4) Telescopicallywithin each pipe 31 is mounted another pipe 7 38, which constitutes ahand rail being supported by a balustrade 39 at the end of the gangplank34. A hand rail 4| is secured transversely between the two balustrades39 to prevent workmen from walking off the end of the gangplank 34.

A ladder 42 is mounted in one of the frames I! to provide ready accessto and from the platform |8 when the scaffold is in position underneatha dock.

Operation Use of the instant invention will now be described. The no;fork I5 is first inserted between 1 edge of the clock 41, as shown inFig. 5, the fork I6 is lowered until the platform I8 is substantiallylevel with the dock 41.

At this point workmen may board the platform |8 under the rail 4|.

The fork I6 is then lowered further until the frame II is positionedjust above the timber 46.

, for the gangplank 34, these hand rails in turn This brings theplatform l8 well beneath the level of the dock 41, so that the truck 45may then be backed up until the inner edges of theframes almost touchthe edge of the dock 41. The fork I6 is then lowered until most of theweight of the scaffold rests on the timber 46, as shown in Fig. 6. Thegangway 34 is then ready to be extended as shown in Fig. 6, so that aconsiderable length of elongate platform is provided under the dock 41.

Necessary repairs may then be made as required. The weight of the truck45, coupled with the fact that the scaffold rests principally on thetimber 45, serves to maintain the scaffold safely in position. Much ofthe work may be done with the center of gravity of the scaffold and itscontents substantially beneath the front wheel of the truck 45, therebyproviding a very stable and safe assembly. During operation, access tothe platform I8 and the gangplank 34 is had by the ladder 42.

The invention described herein may be manufactured and used by or forthe Government of the UnitedStates of America for governmental purposeswithout the payment of any royalties thereon or therefor.

What is claimed is:

1. A portable scaffold adapted to be carried by a lift truck, comprisinga flat, horizontal, generally elongate frame including a pair oftransverse girders, one of said girders being disposed at one end ofsaid frame, the other girder being spaced from said one girder inwardlyof said frame and in a plane slightly above said one girder, said framebeing adapted to be held by the lifting fork of the truck in cantileverfashion with said one girder disposed under said fork and said othergirder disposed over said fork, a verticalbridge frame securedtransversely to and above said horizontal frame, an elongate tensionmember secured at its respective ends to the ends of said horizontalframe and secured intermediate its ends to the top of said bridge frame,a vertical frame secured to said horizontal frame at the overhanging endthereof and depending therefrom, and a horizontal platform secured tosaid vertical frame and extending beneath said horizontal frame.

2. A portable scaffold adapted to be carried by a lift truck, comprisinga flat, horizontal, generally elongate frame including a pair oftransverse girders, one of said girders being disposed at one end ofsaid frame, the other girder being spaced from said one girder inwardlyof said frame and in a plane slightly above said one girder, said framebeing adapted to be held by the lifting fork of the truck in cantileverfashion with said one girder disposed under said fork and said othergirder disposed over said fork, a pair of flat vertical frames securedrespectively to opposite sides of said horizontal frame at theoverhanging end thereof and depending therefrom, a horizontal, generallyelongate platform secured to the lower ends of said vertical frames andextending beneath said horizontal frame, and a gangplank telescopicallymounted beneath said platform and selectively extendable away from saidvertical frame.

3. A portable scafiold adapted to be carried by a lift truck, comprisinga fiat, horizontal, generally elongate frame including a pair oftransverse girders, one of said girders being disposed at one end ofsaid frame, the other girder being spaced from said one girder inwardlyof said frame and in a plane slightly above said one girder, said framebeing adapted to be held by the lifting fork of the truck in cantileverfashion with said one girder disposed under said fork and'said other,

frame secured transversely to and above said horizontal frame, anelongate tension member secured at its respective ends to the ends ofsaid horizontal frame and secured intermediate its ends to the top ofsaid bridge frame, a pair of fiat vertical frames secured respectivelyto opposite sides of said horizontal frame at the overhanging endthereof and depending therefrom, a. horizontal, generally elongateplatform secured to the lower ends of said vertical frames and extendingbeneath said horizontal frame, a gangplank telescopically mountedbeneath said platform and selectively extendable away from said verticalframes, and a ladder secured vertically between said horizontal frameand said platform.

4. A portable scaffold adapted to be carried by a lift truck, comprisinga flat, horizontal, generally elongate frame including a pair oftransverse girders, one of said girders being disposed at one end ofsaid frame, the other girder being spaced from said one girder inwardlyof said frame and in a plane slightly above said one girder, said framebeing adapted to be held by the lifting fork of the truck in cantileverfashion with said one girder disposed under said fork and said othergirder disposed over said fork, a vertical bridge frame securedtransversely to and above said horizontal frame in substantially thesame vertical plane as said other girder, an elongate tension membersecured at its respective ends to the ends of said horizontal frame andsecured intermediate its ends to the top of said bridge frame, a pair offlat vertical frames secured respectively to opposite sides of saidhorizontal frame at the overhanging end thereof and depending therefrom,a, horizontal, generally elongate platform secured to the lower ends ofsaid vertical frames and extending beneath said horizontal frame, agangplank telescopically mounted beneath said platform and selectivelyextendable away from said vertical frames, and a ladder securedvertically between said horizontal frame and said platform.

JOHN L. THOMPSON.

JOHN BIBB.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 466,890 Dean Jan. 12, 18921,268,607 Pettis June 4, 1918 1,427,453 Fleming Aug. 29, 1922 2,068,825Stevenson Jan. 26, 1937 2,362,170 Swaisgood Nov. 7, 1944 FOREIGN PATENTSNumber Country Date 9,147 Great Britain 1911 250,300 Switzerland June 1,1948

